[PATCH] USB: chipidea: fix interrupt deadlock

[Johan Hovold]

Chipidea core was calling the interrupt handler from non-IRQ context
with interrupts enabled, something which can lead to a deadlock if
there's an actual interrupt trying to take a lock that's already held
(e.g. the controller lock in udc_irq()).

Add a wrapper that can be used to fake interrupts instead of calling the
handler directly.

Fixes: 3ecb3e09b042 ("usb: chipidea: Use extcon framework for VBUS and ID detect")
Fixes: 876d4e1e8298 ("usb: chipidea: core: add wakeup support for extcon")
Cc: stable@xxxxxxxxxxxxxxx      # 4.4
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
 drivers/usb/chipidea/core.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 2b18f5088ae4..a56f06368d14 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -514,7 +514,7 @@ int hw_device_reset(struct ci_hdrc *ci)
 	return 0;
 }
 
-static irqreturn_t ci_irq(int irq, void *data)
+static irqreturn_t ci_irq_handler(int irq, void *data)
 {
 	struct ci_hdrc *ci = data;
 	irqreturn_t ret = IRQ_NONE;
@@ -567,6 +567,15 @@ static irqreturn_t ci_irq(int irq, void *data)
 	return ret;
 }
 
+static void ci_irq(struct ci_hdrc *ci)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ci_irq_handler(ci->irq, ci);
+	local_irq_restore(flags);
+}
+
 static int ci_cable_notifier(struct notifier_block *nb, unsigned long event,
 			     void *ptr)
 {
@@ -576,7 +585,7 @@ static int ci_cable_notifier(struct notifier_block *nb, unsigned long event,
 	cbl->connected = event;
 	cbl->changed = true;
 
-	ci_irq(ci->irq, ci);
+	ci_irq(ci);
 	return NOTIFY_DONE;
 }
 
@@ -617,7 +626,7 @@ static int ci_usb_role_switch_set(struct usb_role_switch *sw,
 	if (cable) {
 		cable->changed = true;
 		cable->connected = false;
-		ci_irq(ci->irq, ci);
+		ci_irq(ci);
 		spin_unlock_irqrestore(&ci->lock, flags);
 		if (ci->wq && role != USB_ROLE_NONE)
 			flush_workqueue(ci->wq);
@@ -635,7 +644,7 @@ static int ci_usb_role_switch_set(struct usb_role_switch *sw,
 	if (cable) {
 		cable->changed = true;
 		cable->connected = true;
-		ci_irq(ci->irq, ci);
+		ci_irq(ci);
 	}
 	spin_unlock_irqrestore(&ci->lock, flags);
 	pm_runtime_put_sync(ci->dev);
@@ -1174,7 +1183,7 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 		}
 	}
 
-	ret = devm_request_irq(dev, ci->irq, ci_irq, IRQF_SHARED,
+	ret = devm_request_irq(dev, ci->irq, ci_irq_handler, IRQF_SHARED,
 			ci->platdata->name, ci);
 	if (ret)
 		goto stop;
@@ -1295,11 +1304,11 @@ static void ci_extcon_wakeup_int(struct ci_hdrc *ci)
 
 	if (!IS_ERR(cable_id->edev) && ci->is_otg &&
 		(otgsc & OTGSC_IDIE) && (otgsc & OTGSC_IDIS))
-		ci_irq(ci->irq, ci);
+		ci_irq(ci);
 
 	if (!IS_ERR(cable_vbus->edev) && ci->is_otg &&
 		(otgsc & OTGSC_BSVIE) && (otgsc & OTGSC_BSVIS))
-		ci_irq(ci->irq, ci);
+		ci_irq(ci);
 }
 
 static int ci_controller_resume(struct device *dev)
-- 
2.32.0